Amphibian propulsion mechanism



h A H M IJ.

AHPHIBIAN PROPULSION MECHANISH Filed Feb. 15, 1945 4 Sheets-Sheet 1 mmz- Ill/EJ111740 U Ii!@Eliiihli! March 26, 1946. J. M. HAIT- 2,397,104 7 AIPHIBIAN PROPUTLS ION MECHANISM Filed Feb. 15, 1943 4 Sheets-Sheet 2' 'March 26, 1946. -r 2,397,104.

AMPHIBIANPROPULSION MECHANISM Filed Feb. 15, 1945 4 Sheets-Sheet s March 26, 1946. J. M. HAlT AMPHIBIAN PROPULSION MECHANISM 4 Sheets-Sheet 4 Filed Feb. 15, 1943- Patented Mar. 26, 1946 2,397,104 AMPHIBIAN PROPULSION MECHANISM James lVLll-Iait, San Gabriel, Calif, assignor to Food Machinery Corporation,

San Jose, Calif.,

a corporation of Delaware Application February 15, 1943, Serial No. 475,932

3 Claims.

This invention relates to Vehicles equipped with track-laying belts and is especially useful on amphibians which are so equipped.

Amphibians employing track-laying belts as a means of supporting and propelling the craft on land, and providing propulsion when afloat, are faced with the problem of providing slack enough in the belt for the latter to conform to obstacles over which the amphibian may have to ride on land, yet preventing the belt from running off the bogie wheels when the craft is afloat and the belt tends to sag downwardly away from the bogie wheels.

It accordingly an object of my invention to provide a track-laying mechanism suitable for use as a running gear for an amphibian, and which meets this problem.

One of the methods previously used in taking up slack in a track-laying belt is to spring mount the bogie wheels so that these constantly press against the belt to keep this in contact with all the bogie wheels. This type of mounting for all the bogie wheels adds a great deal of weight, however, and not only reduces the load that can be carried by each bogie wheel, but consumes so much space that the bogie wheels have to be located at such intervals as to substantially limit the number of bogie wheels which can be used.

It is another object of my invention to provide a solution for this problem which will eliminate the difficulties last aforementioned, and will permit bogie wheels to be used in such a number and mounted in such a manner that a light carriage structure may be thus provided which shall bear a relatively heavy burden, and in which the belt will at all times be maintained in proper alignment with the bogie wheels.

Where track-laying belts are used on amphibians it is sometimes advantageous to drive these from the front end of the craft by the front sprockets about which the track-laying belts are trained. This accumulates considerable slack just below the drive sprockets in the lower runs of these belts when the amphibian is traveling on land. When fixed bogie wheels are used, as suggested hereinabove, this slack tends to accumulate to the point where there is danger of the belt running off the leading bogie wheel.

It is an object of my invention to provide a track-laying mechanism suitable for use as a running gear for an amphibian which is supported on fixed bogie wheels, and in which slack in the belts is rendered inoperative to cause the belts to run off the bogie wheels either while the amphibian is traveling on land or on the water.

The manner of accomplishing the foregoing objects, as well as further objects and advantages, will be made manifest in the following description taken in connection with the accompanying drawings, in which:

Fig. l is a side elevational view of an amphibia which incorporates a preferred embodiment of my invention.

Fig. 2 is an enlarged fragmentary view of the front idler mechanism shown in Fig. l, with the spring housing broken away to show the interior construction.

Fig. 3 is a cross sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is an enlarged fragmentary detail view of the central drop bogie wheel of the invention.

Fig. 5 is a cross sectional view of said bogie wheel taken on the line 5-5 of Fig. 4.

Fig. 6 is a cross sectional view taken on the line 6-6 of Fig. 5.

Fig. '7 is a cross sectional view taken on the line 7-1 of Fig. 6;

Referring specifically to the drawings, the amphibian lb shown therein includes a hull H, on the sides of which are provided pontoons I2, and about which are mounted track-laying mechanisms l3. As these are reverse duplicates of each other, a description of one will suflice for both. The left-hand track-laying mechanism illustrated in Fig. 1 includes an idler sprocket l4 and a drive sprocket l5 mounted on shafts l6 and I1 respectively, the latter shaft being connected to the power plant (not shown) which is located inside of the hull H.

Provided on the pontoon I2 is a jack 2B, for shifting the shaft 16 and sprocket l4 horizontally. Fixed to the lower surface of the pontoon i2 is a pair of channel irons 25 along the lower edges of which are mounted clamp brackets 26, in which are fixed opposite ends of bogie wheel axles 21, on which are rotatably mounted bogie wheels 28. Each of these bogie wheels (see Fig. 5) includes a hub member having a pair of centrally located spaced metal flanges 3| and a pair of solid rubber tires 32 located just outside of the flanges 31.

It will be noted that these bogie wheels are located relatively close together so as to provide the maximum number of bogie wheels. It is also to be noted that the channel irons 25 and series of .bogie wheels mounted thereon, conform to the contour of the lower face of the pontoon l2, so that opposite end groups of this series of bogie wheels are inclined upwardly towards the opposite ends of the amphibian ill. The series of bogie wheels 28 is broken centrally to provide a space 35 in which is mounted a vertically shiftable bogie wheel 36, which is identical in construction with the bogie wheels 28. Opposite ends of a shaft 31 of the bogie wheel 36, however, are gripped in clamps 39 provided on arms Ml which have pivot pins M journalling in bearings 42, which are fixed by cap screws 43 to bottom wheel 36 about the pins 4|.

flanges of the channel iron members 25 (see Figs.

4, 6 and '7). The arms 40 have rubber cushions 45 provided thereon, which contact the lower faces of the channel irons 25, as shown in Fig. 6

to cushion contact of the clamps 39 with the channel irons 25 when the bogie wheel 36 rises into alignment with the other bogie wheels'28.

into the clamp brackets 26.

Adjacent the sprocket I is an idler mechanism 65. This includes a bogie wheel 66, having an axle 61, these being identical with the bogie wheels 28 and their axles 27. Opposite ends of' the axle'6'! are rigidlymounted in clamps 68 provided on lower ends of arms 69, the upper ends of which are clamped :on' a pivot shaft 16 which journals in bearings 1| mounted on the pontoon l2. Suspended at its opposite ends between the forward end of each of the arms 69 and a bracket 75 fixed on the pontoon I2 is one of apair of contractile springs 16. These springs are covered by suitable housings ,11 to prevent brush and the like, through which the amphibian 16 might be traveling, from interfering with their proper operation. The arms 69 are provided with rubber shock cushions 18 which bear against the t pontoon l2 when the bogie wheel 66 is swung inwardly asshown in Fig. 2.

Suitable idler wheels!!! are-mounted On top of the pontoon 2 as shown in Fig. 1. 7

Trained about the sprockets I 4 and I5, the idler wheels 19, and the bogie wheels 28, 36 and 66, is a track-laying belt 86, which is preferably of the type' shown in U. S. Letters Patent to Robert Mayne, No. 2,167,490, issued February 8, 1 938,

for'Track for tractors. This belt includes two I endless rubber bands 85 provided with suitable reinforcing cables 86 which are clamped between a series of clamps 8'! opposite ends of which are inibedded with the cables 85 in therubber bands 86. Provided on the central exposed portions of the clamps 81 is an endless series of metallic guide members '88 which extend inwardly from the'belt 80, so as to guide this belt on the sprock-I ets l4 and Is, the idler wheels 19 and the bogie wheels 26, 36 and 66. a

Mounted on the outer surface of the tracklaying belt 86 is an endless series of grousers' 9 6, which contact the ground and support the amphibian when it is traveling on land, but which are designed. to efliciently engage the water when the amphibian is afioat'so that operation of the belts 89 provides suitable propulsion for the amphibian through-the water.

Fi 1 illustrates the mode in which the track-,

laying mechanism of my invention functions when'the amphibian l6 embodying the same is afloat. The track-laying belt 89 is here shown as when tightened to almost its maximum degree of tautness in practical operation, by operation of the jack 26. This still leaves a considerable slack, however, in the belt, a portion of which is taken up by the yieldable bogie wheel 65' at the bow, and by the central shiftable bogie wheel 36. The bogie wheel 36 preferably does not apply any pressure downwardly against the'belt 86, however, and the force applied to this belt by the bogie wheel 65 tends to take up the slack at this point and maintain the sagging central portion of the belt 86 at all times in contact with the bogie wheel 36. the belt 86 are thus always caused to extend between the central flanges 3I of the bogie wheel 66 so that the saggingcentral portion of the vertical lower run of the belt 86 never gets out of alignment with the fixed bogie wheel 28. g

Control of the slack in the belt 66 in this mane ner makes it unnecessary to mount the bogie wheels 28 yieldably, thus eliminating a large amount of weight from the amphibian l6 and making room for a much larger number of'bogie wheels 26 than would be otherwise possible, thereby increasing the load that can be carried by the amphibian l5, and the factor of safetywith which it carrie its normal load.

What I claimis': 1. In atrack-laying mechanism'the combination of: a frame; a track-laying belt; sprocket means on said frame about which said belt is trained to operate in substantially a vertical plane and to drive said belt, and to provide anupper belt run and a lower belt run; a, series of bogie wheels mounted close-together on said frame on substantially fixed axes for riding on said lower belt run when said lower run is resting on land, there being a gap provided in said series of bogie wheels; a yoke pivotally mounted on said frame so as to be swingable up and down in said gap; and a shiftable bogie wheel rotatably mounted on 7 said yoke in said gap and swingable about the dropping downwardly by gravity .upon the sagging of said lower belt runs to remainin contact therewith and guide said lowerbelt runs to maintain axis of said yoke andresponding togravity when said lower belt run sags downwardly away from A said fixed bogie wheels to follow said belt run and keep in contact therewith.

2. An amphibian comprising a hullya pair of track-laying belts, mounted on opposite sides of the hull; sprocket means for drivingsaid belts;

said belts being divided into upper runs and lower runs; a series of bogie wheels mounted on said hull on substantially fixed axes over the lower 5 belt run of each of said belts, said-bogiewh'eel's riding on said lower belt runs when said amphibian is travelling on land, said beltssagging away from'said bogie wheels when said amphibian is afloat; and means centrally disposed with respect to and in contact with said lower belt runs and these in alignment with said fixed bogie wheels so that when said amphibian travels from water onto land said lower belt runs will move upwardly into contact with said fixed bogie wheels in proper alignment with the latter.

3. A combination as in claim 2, in whicha gap 7 is provided centrally in the group of fixed bogie wheels disposed over each lower belt run and in which said guide means comprises a vertically shiftable bogie wheel which is disposed within said gap and mounted to ride on said lower belt run and follow the same by gravity.

, JAMES M. HAIT;

The guide members 88 on. 

